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KVM: Move guest pte dirty bit management to the guest pagetable walker
[deliverable/linux.git] / drivers / kvm / mmu.c
1 /*
2 * Kernel-based Virtual Machine driver for Linux
3 *
4 * This module enables machines with Intel VT-x extensions to run virtual
5 * machines without emulation or binary translation.
6 *
7 * MMU support
8 *
9 * Copyright (C) 2006 Qumranet, Inc.
10 *
11 * Authors:
12 * Yaniv Kamay <yaniv@qumranet.com>
13 * Avi Kivity <avi@qumranet.com>
14 *
15 * This work is licensed under the terms of the GNU GPL, version 2. See
16 * the COPYING file in the top-level directory.
17 *
18 */
19
20 #include "vmx.h"
21 #include "kvm.h"
22
23 #include <linux/types.h>
24 #include <linux/string.h>
25 #include <linux/mm.h>
26 #include <linux/highmem.h>
27 #include <linux/module.h>
28
29 #include <asm/page.h>
30 #include <asm/cmpxchg.h>
31
32 #undef MMU_DEBUG
33
34 #undef AUDIT
35
36 #ifdef AUDIT
37 static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg);
38 #else
39 static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg) {}
40 #endif
41
42 #ifdef MMU_DEBUG
43
44 #define pgprintk(x...) do { if (dbg) printk(x); } while (0)
45 #define rmap_printk(x...) do { if (dbg) printk(x); } while (0)
46
47 #else
48
49 #define pgprintk(x...) do { } while (0)
50 #define rmap_printk(x...) do { } while (0)
51
52 #endif
53
54 #if defined(MMU_DEBUG) || defined(AUDIT)
55 static int dbg = 1;
56 #endif
57
58 #ifndef MMU_DEBUG
59 #define ASSERT(x) do { } while (0)
60 #else
61 #define ASSERT(x) \
62 if (!(x)) { \
63 printk(KERN_WARNING "assertion failed %s:%d: %s\n", \
64 __FILE__, __LINE__, #x); \
65 }
66 #endif
67
68 #define PT64_PT_BITS 9
69 #define PT64_ENT_PER_PAGE (1 << PT64_PT_BITS)
70 #define PT32_PT_BITS 10
71 #define PT32_ENT_PER_PAGE (1 << PT32_PT_BITS)
72
73 #define PT_WRITABLE_SHIFT 1
74
75 #define PT_PRESENT_MASK (1ULL << 0)
76 #define PT_WRITABLE_MASK (1ULL << PT_WRITABLE_SHIFT)
77 #define PT_USER_MASK (1ULL << 2)
78 #define PT_PWT_MASK (1ULL << 3)
79 #define PT_PCD_MASK (1ULL << 4)
80 #define PT_ACCESSED_MASK (1ULL << 5)
81 #define PT_DIRTY_MASK (1ULL << 6)
82 #define PT_PAGE_SIZE_MASK (1ULL << 7)
83 #define PT_PAT_MASK (1ULL << 7)
84 #define PT_GLOBAL_MASK (1ULL << 8)
85 #define PT64_NX_MASK (1ULL << 63)
86
87 #define PT_PAT_SHIFT 7
88 #define PT_DIR_PAT_SHIFT 12
89 #define PT_DIR_PAT_MASK (1ULL << PT_DIR_PAT_SHIFT)
90
91 #define PT32_DIR_PSE36_SIZE 4
92 #define PT32_DIR_PSE36_SHIFT 13
93 #define PT32_DIR_PSE36_MASK \
94 (((1ULL << PT32_DIR_PSE36_SIZE) - 1) << PT32_DIR_PSE36_SHIFT)
95
96
97 #define PT_FIRST_AVAIL_BITS_SHIFT 9
98 #define PT64_SECOND_AVAIL_BITS_SHIFT 52
99
100 #define PT_SHADOW_IO_MARK (1ULL << PT_FIRST_AVAIL_BITS_SHIFT)
101
102 #define VALID_PAGE(x) ((x) != INVALID_PAGE)
103
104 #define PT64_LEVEL_BITS 9
105
106 #define PT64_LEVEL_SHIFT(level) \
107 (PAGE_SHIFT + (level - 1) * PT64_LEVEL_BITS)
108
109 #define PT64_LEVEL_MASK(level) \
110 (((1ULL << PT64_LEVEL_BITS) - 1) << PT64_LEVEL_SHIFT(level))
111
112 #define PT64_INDEX(address, level)\
113 (((address) >> PT64_LEVEL_SHIFT(level)) & ((1 << PT64_LEVEL_BITS) - 1))
114
115
116 #define PT32_LEVEL_BITS 10
117
118 #define PT32_LEVEL_SHIFT(level) \
119 (PAGE_SHIFT + (level - 1) * PT32_LEVEL_BITS)
120
121 #define PT32_LEVEL_MASK(level) \
122 (((1ULL << PT32_LEVEL_BITS) - 1) << PT32_LEVEL_SHIFT(level))
123
124 #define PT32_INDEX(address, level)\
125 (((address) >> PT32_LEVEL_SHIFT(level)) & ((1 << PT32_LEVEL_BITS) - 1))
126
127
128 #define PT64_BASE_ADDR_MASK (((1ULL << 52) - 1) & ~(u64)(PAGE_SIZE-1))
129 #define PT64_DIR_BASE_ADDR_MASK \
130 (PT64_BASE_ADDR_MASK & ~((1ULL << (PAGE_SHIFT + PT64_LEVEL_BITS)) - 1))
131
132 #define PT32_BASE_ADDR_MASK PAGE_MASK
133 #define PT32_DIR_BASE_ADDR_MASK \
134 (PAGE_MASK & ~((1ULL << (PAGE_SHIFT + PT32_LEVEL_BITS)) - 1))
135
136
137 #define PFERR_PRESENT_MASK (1U << 0)
138 #define PFERR_WRITE_MASK (1U << 1)
139 #define PFERR_USER_MASK (1U << 2)
140 #define PFERR_FETCH_MASK (1U << 4)
141
142 #define PT64_ROOT_LEVEL 4
143 #define PT32_ROOT_LEVEL 2
144 #define PT32E_ROOT_LEVEL 3
145
146 #define PT_DIRECTORY_LEVEL 2
147 #define PT_PAGE_TABLE_LEVEL 1
148
149 #define RMAP_EXT 4
150
151 struct kvm_rmap_desc {
152 u64 *shadow_ptes[RMAP_EXT];
153 struct kvm_rmap_desc *more;
154 };
155
156 static struct kmem_cache *pte_chain_cache;
157 static struct kmem_cache *rmap_desc_cache;
158 static struct kmem_cache *mmu_page_header_cache;
159
160 static u64 __read_mostly shadow_trap_nonpresent_pte;
161 static u64 __read_mostly shadow_notrap_nonpresent_pte;
162
163 void kvm_mmu_set_nonpresent_ptes(u64 trap_pte, u64 notrap_pte)
164 {
165 shadow_trap_nonpresent_pte = trap_pte;
166 shadow_notrap_nonpresent_pte = notrap_pte;
167 }
168 EXPORT_SYMBOL_GPL(kvm_mmu_set_nonpresent_ptes);
169
170 static int is_write_protection(struct kvm_vcpu *vcpu)
171 {
172 return vcpu->cr0 & X86_CR0_WP;
173 }
174
175 static int is_cpuid_PSE36(void)
176 {
177 return 1;
178 }
179
180 static int is_nx(struct kvm_vcpu *vcpu)
181 {
182 return vcpu->shadow_efer & EFER_NX;
183 }
184
185 static int is_present_pte(unsigned long pte)
186 {
187 return pte & PT_PRESENT_MASK;
188 }
189
190 static int is_shadow_present_pte(u64 pte)
191 {
192 pte &= ~PT_SHADOW_IO_MARK;
193 return pte != shadow_trap_nonpresent_pte
194 && pte != shadow_notrap_nonpresent_pte;
195 }
196
197 static int is_writeble_pte(unsigned long pte)
198 {
199 return pte & PT_WRITABLE_MASK;
200 }
201
202 static int is_dirty_pte(unsigned long pte)
203 {
204 return pte & PT_DIRTY_MASK;
205 }
206
207 static int is_io_pte(unsigned long pte)
208 {
209 return pte & PT_SHADOW_IO_MARK;
210 }
211
212 static int is_rmap_pte(u64 pte)
213 {
214 return (pte & (PT_WRITABLE_MASK | PT_PRESENT_MASK))
215 == (PT_WRITABLE_MASK | PT_PRESENT_MASK);
216 }
217
218 static void set_shadow_pte(u64 *sptep, u64 spte)
219 {
220 #ifdef CONFIG_X86_64
221 set_64bit((unsigned long *)sptep, spte);
222 #else
223 set_64bit((unsigned long long *)sptep, spte);
224 #endif
225 }
226
227 static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
228 struct kmem_cache *base_cache, int min)
229 {
230 void *obj;
231
232 if (cache->nobjs >= min)
233 return 0;
234 while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
235 obj = kmem_cache_zalloc(base_cache, GFP_KERNEL);
236 if (!obj)
237 return -ENOMEM;
238 cache->objects[cache->nobjs++] = obj;
239 }
240 return 0;
241 }
242
243 static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc)
244 {
245 while (mc->nobjs)
246 kfree(mc->objects[--mc->nobjs]);
247 }
248
249 static int mmu_topup_memory_cache_page(struct kvm_mmu_memory_cache *cache,
250 int min)
251 {
252 struct page *page;
253
254 if (cache->nobjs >= min)
255 return 0;
256 while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
257 page = alloc_page(GFP_KERNEL);
258 if (!page)
259 return -ENOMEM;
260 set_page_private(page, 0);
261 cache->objects[cache->nobjs++] = page_address(page);
262 }
263 return 0;
264 }
265
266 static void mmu_free_memory_cache_page(struct kvm_mmu_memory_cache *mc)
267 {
268 while (mc->nobjs)
269 free_page((unsigned long)mc->objects[--mc->nobjs]);
270 }
271
272 static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu)
273 {
274 int r;
275
276 kvm_mmu_free_some_pages(vcpu);
277 r = mmu_topup_memory_cache(&vcpu->mmu_pte_chain_cache,
278 pte_chain_cache, 4);
279 if (r)
280 goto out;
281 r = mmu_topup_memory_cache(&vcpu->mmu_rmap_desc_cache,
282 rmap_desc_cache, 1);
283 if (r)
284 goto out;
285 r = mmu_topup_memory_cache_page(&vcpu->mmu_page_cache, 8);
286 if (r)
287 goto out;
288 r = mmu_topup_memory_cache(&vcpu->mmu_page_header_cache,
289 mmu_page_header_cache, 4);
290 out:
291 return r;
292 }
293
294 static void mmu_free_memory_caches(struct kvm_vcpu *vcpu)
295 {
296 mmu_free_memory_cache(&vcpu->mmu_pte_chain_cache);
297 mmu_free_memory_cache(&vcpu->mmu_rmap_desc_cache);
298 mmu_free_memory_cache_page(&vcpu->mmu_page_cache);
299 mmu_free_memory_cache(&vcpu->mmu_page_header_cache);
300 }
301
302 static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc,
303 size_t size)
304 {
305 void *p;
306
307 BUG_ON(!mc->nobjs);
308 p = mc->objects[--mc->nobjs];
309 memset(p, 0, size);
310 return p;
311 }
312
313 static struct kvm_pte_chain *mmu_alloc_pte_chain(struct kvm_vcpu *vcpu)
314 {
315 return mmu_memory_cache_alloc(&vcpu->mmu_pte_chain_cache,
316 sizeof(struct kvm_pte_chain));
317 }
318
319 static void mmu_free_pte_chain(struct kvm_pte_chain *pc)
320 {
321 kfree(pc);
322 }
323
324 static struct kvm_rmap_desc *mmu_alloc_rmap_desc(struct kvm_vcpu *vcpu)
325 {
326 return mmu_memory_cache_alloc(&vcpu->mmu_rmap_desc_cache,
327 sizeof(struct kvm_rmap_desc));
328 }
329
330 static void mmu_free_rmap_desc(struct kvm_rmap_desc *rd)
331 {
332 kfree(rd);
333 }
334
335 /*
336 * Take gfn and return the reverse mapping to it.
337 * Note: gfn must be unaliased before this function get called
338 */
339
340 static unsigned long *gfn_to_rmap(struct kvm *kvm, gfn_t gfn)
341 {
342 struct kvm_memory_slot *slot;
343
344 slot = gfn_to_memslot(kvm, gfn);
345 return &slot->rmap[gfn - slot->base_gfn];
346 }
347
348 /*
349 * Reverse mapping data structures:
350 *
351 * If rmapp bit zero is zero, then rmapp point to the shadw page table entry
352 * that points to page_address(page).
353 *
354 * If rmapp bit zero is one, (then rmap & ~1) points to a struct kvm_rmap_desc
355 * containing more mappings.
356 */
357 static void rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
358 {
359 struct kvm_mmu_page *page;
360 struct kvm_rmap_desc *desc;
361 unsigned long *rmapp;
362 int i;
363
364 if (!is_rmap_pte(*spte))
365 return;
366 gfn = unalias_gfn(vcpu->kvm, gfn);
367 page = page_header(__pa(spte));
368 page->gfns[spte - page->spt] = gfn;
369 rmapp = gfn_to_rmap(vcpu->kvm, gfn);
370 if (!*rmapp) {
371 rmap_printk("rmap_add: %p %llx 0->1\n", spte, *spte);
372 *rmapp = (unsigned long)spte;
373 } else if (!(*rmapp & 1)) {
374 rmap_printk("rmap_add: %p %llx 1->many\n", spte, *spte);
375 desc = mmu_alloc_rmap_desc(vcpu);
376 desc->shadow_ptes[0] = (u64 *)*rmapp;
377 desc->shadow_ptes[1] = spte;
378 *rmapp = (unsigned long)desc | 1;
379 } else {
380 rmap_printk("rmap_add: %p %llx many->many\n", spte, *spte);
381 desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
382 while (desc->shadow_ptes[RMAP_EXT-1] && desc->more)
383 desc = desc->more;
384 if (desc->shadow_ptes[RMAP_EXT-1]) {
385 desc->more = mmu_alloc_rmap_desc(vcpu);
386 desc = desc->more;
387 }
388 for (i = 0; desc->shadow_ptes[i]; ++i)
389 ;
390 desc->shadow_ptes[i] = spte;
391 }
392 }
393
394 static void rmap_desc_remove_entry(unsigned long *rmapp,
395 struct kvm_rmap_desc *desc,
396 int i,
397 struct kvm_rmap_desc *prev_desc)
398 {
399 int j;
400
401 for (j = RMAP_EXT - 1; !desc->shadow_ptes[j] && j > i; --j)
402 ;
403 desc->shadow_ptes[i] = desc->shadow_ptes[j];
404 desc->shadow_ptes[j] = NULL;
405 if (j != 0)
406 return;
407 if (!prev_desc && !desc->more)
408 *rmapp = (unsigned long)desc->shadow_ptes[0];
409 else
410 if (prev_desc)
411 prev_desc->more = desc->more;
412 else
413 *rmapp = (unsigned long)desc->more | 1;
414 mmu_free_rmap_desc(desc);
415 }
416
417 static void rmap_remove(struct kvm *kvm, u64 *spte)
418 {
419 struct kvm_rmap_desc *desc;
420 struct kvm_rmap_desc *prev_desc;
421 struct kvm_mmu_page *page;
422 unsigned long *rmapp;
423 int i;
424
425 if (!is_rmap_pte(*spte))
426 return;
427 page = page_header(__pa(spte));
428 rmapp = gfn_to_rmap(kvm, page->gfns[spte - page->spt]);
429 if (!*rmapp) {
430 printk(KERN_ERR "rmap_remove: %p %llx 0->BUG\n", spte, *spte);
431 BUG();
432 } else if (!(*rmapp & 1)) {
433 rmap_printk("rmap_remove: %p %llx 1->0\n", spte, *spte);
434 if ((u64 *)*rmapp != spte) {
435 printk(KERN_ERR "rmap_remove: %p %llx 1->BUG\n",
436 spte, *spte);
437 BUG();
438 }
439 *rmapp = 0;
440 } else {
441 rmap_printk("rmap_remove: %p %llx many->many\n", spte, *spte);
442 desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
443 prev_desc = NULL;
444 while (desc) {
445 for (i = 0; i < RMAP_EXT && desc->shadow_ptes[i]; ++i)
446 if (desc->shadow_ptes[i] == spte) {
447 rmap_desc_remove_entry(rmapp,
448 desc, i,
449 prev_desc);
450 return;
451 }
452 prev_desc = desc;
453 desc = desc->more;
454 }
455 BUG();
456 }
457 }
458
459 static void rmap_write_protect(struct kvm *kvm, u64 gfn)
460 {
461 struct kvm_rmap_desc *desc;
462 unsigned long *rmapp;
463 u64 *spte;
464
465 gfn = unalias_gfn(kvm, gfn);
466 rmapp = gfn_to_rmap(kvm, gfn);
467
468 while (*rmapp) {
469 if (!(*rmapp & 1))
470 spte = (u64 *)*rmapp;
471 else {
472 desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
473 spte = desc->shadow_ptes[0];
474 }
475 BUG_ON(!spte);
476 BUG_ON(!(*spte & PT_PRESENT_MASK));
477 BUG_ON(!(*spte & PT_WRITABLE_MASK));
478 rmap_printk("rmap_write_protect: spte %p %llx\n", spte, *spte);
479 rmap_remove(kvm, spte);
480 set_shadow_pte(spte, *spte & ~PT_WRITABLE_MASK);
481 kvm_flush_remote_tlbs(kvm);
482 }
483 }
484
485 #ifdef MMU_DEBUG
486 static int is_empty_shadow_page(u64 *spt)
487 {
488 u64 *pos;
489 u64 *end;
490
491 for (pos = spt, end = pos + PAGE_SIZE / sizeof(u64); pos != end; pos++)
492 if ((*pos & ~PT_SHADOW_IO_MARK) != shadow_trap_nonpresent_pte) {
493 printk(KERN_ERR "%s: %p %llx\n", __FUNCTION__,
494 pos, *pos);
495 return 0;
496 }
497 return 1;
498 }
499 #endif
500
501 static void kvm_mmu_free_page(struct kvm *kvm,
502 struct kvm_mmu_page *page_head)
503 {
504 ASSERT(is_empty_shadow_page(page_head->spt));
505 list_del(&page_head->link);
506 __free_page(virt_to_page(page_head->spt));
507 __free_page(virt_to_page(page_head->gfns));
508 kfree(page_head);
509 ++kvm->n_free_mmu_pages;
510 }
511
512 static unsigned kvm_page_table_hashfn(gfn_t gfn)
513 {
514 return gfn;
515 }
516
517 static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu,
518 u64 *parent_pte)
519 {
520 struct kvm_mmu_page *page;
521
522 if (!vcpu->kvm->n_free_mmu_pages)
523 return NULL;
524
525 page = mmu_memory_cache_alloc(&vcpu->mmu_page_header_cache,
526 sizeof *page);
527 page->spt = mmu_memory_cache_alloc(&vcpu->mmu_page_cache, PAGE_SIZE);
528 page->gfns = mmu_memory_cache_alloc(&vcpu->mmu_page_cache, PAGE_SIZE);
529 set_page_private(virt_to_page(page->spt), (unsigned long)page);
530 list_add(&page->link, &vcpu->kvm->active_mmu_pages);
531 ASSERT(is_empty_shadow_page(page->spt));
532 page->slot_bitmap = 0;
533 page->multimapped = 0;
534 page->parent_pte = parent_pte;
535 --vcpu->kvm->n_free_mmu_pages;
536 return page;
537 }
538
539 static void mmu_page_add_parent_pte(struct kvm_vcpu *vcpu,
540 struct kvm_mmu_page *page, u64 *parent_pte)
541 {
542 struct kvm_pte_chain *pte_chain;
543 struct hlist_node *node;
544 int i;
545
546 if (!parent_pte)
547 return;
548 if (!page->multimapped) {
549 u64 *old = page->parent_pte;
550
551 if (!old) {
552 page->parent_pte = parent_pte;
553 return;
554 }
555 page->multimapped = 1;
556 pte_chain = mmu_alloc_pte_chain(vcpu);
557 INIT_HLIST_HEAD(&page->parent_ptes);
558 hlist_add_head(&pte_chain->link, &page->parent_ptes);
559 pte_chain->parent_ptes[0] = old;
560 }
561 hlist_for_each_entry(pte_chain, node, &page->parent_ptes, link) {
562 if (pte_chain->parent_ptes[NR_PTE_CHAIN_ENTRIES-1])
563 continue;
564 for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i)
565 if (!pte_chain->parent_ptes[i]) {
566 pte_chain->parent_ptes[i] = parent_pte;
567 return;
568 }
569 }
570 pte_chain = mmu_alloc_pte_chain(vcpu);
571 BUG_ON(!pte_chain);
572 hlist_add_head(&pte_chain->link, &page->parent_ptes);
573 pte_chain->parent_ptes[0] = parent_pte;
574 }
575
576 static void mmu_page_remove_parent_pte(struct kvm_mmu_page *page,
577 u64 *parent_pte)
578 {
579 struct kvm_pte_chain *pte_chain;
580 struct hlist_node *node;
581 int i;
582
583 if (!page->multimapped) {
584 BUG_ON(page->parent_pte != parent_pte);
585 page->parent_pte = NULL;
586 return;
587 }
588 hlist_for_each_entry(pte_chain, node, &page->parent_ptes, link)
589 for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i) {
590 if (!pte_chain->parent_ptes[i])
591 break;
592 if (pte_chain->parent_ptes[i] != parent_pte)
593 continue;
594 while (i + 1 < NR_PTE_CHAIN_ENTRIES
595 && pte_chain->parent_ptes[i + 1]) {
596 pte_chain->parent_ptes[i]
597 = pte_chain->parent_ptes[i + 1];
598 ++i;
599 }
600 pte_chain->parent_ptes[i] = NULL;
601 if (i == 0) {
602 hlist_del(&pte_chain->link);
603 mmu_free_pte_chain(pte_chain);
604 if (hlist_empty(&page->parent_ptes)) {
605 page->multimapped = 0;
606 page->parent_pte = NULL;
607 }
608 }
609 return;
610 }
611 BUG();
612 }
613
614 static struct kvm_mmu_page *kvm_mmu_lookup_page(struct kvm *kvm,
615 gfn_t gfn)
616 {
617 unsigned index;
618 struct hlist_head *bucket;
619 struct kvm_mmu_page *page;
620 struct hlist_node *node;
621
622 pgprintk("%s: looking for gfn %lx\n", __FUNCTION__, gfn);
623 index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES;
624 bucket = &kvm->mmu_page_hash[index];
625 hlist_for_each_entry(page, node, bucket, hash_link)
626 if (page->gfn == gfn && !page->role.metaphysical) {
627 pgprintk("%s: found role %x\n",
628 __FUNCTION__, page->role.word);
629 return page;
630 }
631 return NULL;
632 }
633
634 static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
635 gfn_t gfn,
636 gva_t gaddr,
637 unsigned level,
638 int metaphysical,
639 unsigned hugepage_access,
640 u64 *parent_pte)
641 {
642 union kvm_mmu_page_role role;
643 unsigned index;
644 unsigned quadrant;
645 struct hlist_head *bucket;
646 struct kvm_mmu_page *page;
647 struct hlist_node *node;
648
649 role.word = 0;
650 role.glevels = vcpu->mmu.root_level;
651 role.level = level;
652 role.metaphysical = metaphysical;
653 role.hugepage_access = hugepage_access;
654 if (vcpu->mmu.root_level <= PT32_ROOT_LEVEL) {
655 quadrant = gaddr >> (PAGE_SHIFT + (PT64_PT_BITS * level));
656 quadrant &= (1 << ((PT32_PT_BITS - PT64_PT_BITS) * level)) - 1;
657 role.quadrant = quadrant;
658 }
659 pgprintk("%s: looking gfn %lx role %x\n", __FUNCTION__,
660 gfn, role.word);
661 index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES;
662 bucket = &vcpu->kvm->mmu_page_hash[index];
663 hlist_for_each_entry(page, node, bucket, hash_link)
664 if (page->gfn == gfn && page->role.word == role.word) {
665 mmu_page_add_parent_pte(vcpu, page, parent_pte);
666 pgprintk("%s: found\n", __FUNCTION__);
667 return page;
668 }
669 page = kvm_mmu_alloc_page(vcpu, parent_pte);
670 if (!page)
671 return page;
672 pgprintk("%s: adding gfn %lx role %x\n", __FUNCTION__, gfn, role.word);
673 page->gfn = gfn;
674 page->role = role;
675 hlist_add_head(&page->hash_link, bucket);
676 vcpu->mmu.prefetch_page(vcpu, page);
677 if (!metaphysical)
678 rmap_write_protect(vcpu->kvm, gfn);
679 return page;
680 }
681
682 static void kvm_mmu_page_unlink_children(struct kvm *kvm,
683 struct kvm_mmu_page *page)
684 {
685 unsigned i;
686 u64 *pt;
687 u64 ent;
688
689 pt = page->spt;
690
691 if (page->role.level == PT_PAGE_TABLE_LEVEL) {
692 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
693 if (is_shadow_present_pte(pt[i]))
694 rmap_remove(kvm, &pt[i]);
695 pt[i] = shadow_trap_nonpresent_pte;
696 }
697 kvm_flush_remote_tlbs(kvm);
698 return;
699 }
700
701 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
702 ent = pt[i];
703
704 pt[i] = shadow_trap_nonpresent_pte;
705 if (!is_shadow_present_pte(ent))
706 continue;
707 ent &= PT64_BASE_ADDR_MASK;
708 mmu_page_remove_parent_pte(page_header(ent), &pt[i]);
709 }
710 kvm_flush_remote_tlbs(kvm);
711 }
712
713 static void kvm_mmu_put_page(struct kvm_mmu_page *page,
714 u64 *parent_pte)
715 {
716 mmu_page_remove_parent_pte(page, parent_pte);
717 }
718
719 static void kvm_mmu_reset_last_pte_updated(struct kvm *kvm)
720 {
721 int i;
722
723 for (i = 0; i < KVM_MAX_VCPUS; ++i)
724 if (kvm->vcpus[i])
725 kvm->vcpus[i]->last_pte_updated = NULL;
726 }
727
728 static void kvm_mmu_zap_page(struct kvm *kvm,
729 struct kvm_mmu_page *page)
730 {
731 u64 *parent_pte;
732
733 while (page->multimapped || page->parent_pte) {
734 if (!page->multimapped)
735 parent_pte = page->parent_pte;
736 else {
737 struct kvm_pte_chain *chain;
738
739 chain = container_of(page->parent_ptes.first,
740 struct kvm_pte_chain, link);
741 parent_pte = chain->parent_ptes[0];
742 }
743 BUG_ON(!parent_pte);
744 kvm_mmu_put_page(page, parent_pte);
745 set_shadow_pte(parent_pte, shadow_trap_nonpresent_pte);
746 }
747 kvm_mmu_page_unlink_children(kvm, page);
748 if (!page->root_count) {
749 hlist_del(&page->hash_link);
750 kvm_mmu_free_page(kvm, page);
751 } else
752 list_move(&page->link, &kvm->active_mmu_pages);
753 kvm_mmu_reset_last_pte_updated(kvm);
754 }
755
756 /*
757 * Changing the number of mmu pages allocated to the vm
758 * Note: if kvm_nr_mmu_pages is too small, you will get dead lock
759 */
760 void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int kvm_nr_mmu_pages)
761 {
762 /*
763 * If we set the number of mmu pages to be smaller be than the
764 * number of actived pages , we must to free some mmu pages before we
765 * change the value
766 */
767
768 if ((kvm->n_alloc_mmu_pages - kvm->n_free_mmu_pages) >
769 kvm_nr_mmu_pages) {
770 int n_used_mmu_pages = kvm->n_alloc_mmu_pages
771 - kvm->n_free_mmu_pages;
772
773 while (n_used_mmu_pages > kvm_nr_mmu_pages) {
774 struct kvm_mmu_page *page;
775
776 page = container_of(kvm->active_mmu_pages.prev,
777 struct kvm_mmu_page, link);
778 kvm_mmu_zap_page(kvm, page);
779 n_used_mmu_pages--;
780 }
781 kvm->n_free_mmu_pages = 0;
782 }
783 else
784 kvm->n_free_mmu_pages += kvm_nr_mmu_pages
785 - kvm->n_alloc_mmu_pages;
786
787 kvm->n_alloc_mmu_pages = kvm_nr_mmu_pages;
788 }
789
790 static int kvm_mmu_unprotect_page(struct kvm *kvm, gfn_t gfn)
791 {
792 unsigned index;
793 struct hlist_head *bucket;
794 struct kvm_mmu_page *page;
795 struct hlist_node *node, *n;
796 int r;
797
798 pgprintk("%s: looking for gfn %lx\n", __FUNCTION__, gfn);
799 r = 0;
800 index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES;
801 bucket = &kvm->mmu_page_hash[index];
802 hlist_for_each_entry_safe(page, node, n, bucket, hash_link)
803 if (page->gfn == gfn && !page->role.metaphysical) {
804 pgprintk("%s: gfn %lx role %x\n", __FUNCTION__, gfn,
805 page->role.word);
806 kvm_mmu_zap_page(kvm, page);
807 r = 1;
808 }
809 return r;
810 }
811
812 static void mmu_unshadow(struct kvm *kvm, gfn_t gfn)
813 {
814 struct kvm_mmu_page *page;
815
816 while ((page = kvm_mmu_lookup_page(kvm, gfn)) != NULL) {
817 pgprintk("%s: zap %lx %x\n",
818 __FUNCTION__, gfn, page->role.word);
819 kvm_mmu_zap_page(kvm, page);
820 }
821 }
822
823 static void page_header_update_slot(struct kvm *kvm, void *pte, gpa_t gpa)
824 {
825 int slot = memslot_id(kvm, gfn_to_memslot(kvm, gpa >> PAGE_SHIFT));
826 struct kvm_mmu_page *page_head = page_header(__pa(pte));
827
828 __set_bit(slot, &page_head->slot_bitmap);
829 }
830
831 hpa_t safe_gpa_to_hpa(struct kvm *kvm, gpa_t gpa)
832 {
833 hpa_t hpa = gpa_to_hpa(kvm, gpa);
834
835 return is_error_hpa(hpa) ? bad_page_address | (gpa & ~PAGE_MASK): hpa;
836 }
837
838 hpa_t gpa_to_hpa(struct kvm *kvm, gpa_t gpa)
839 {
840 struct page *page;
841
842 ASSERT((gpa & HPA_ERR_MASK) == 0);
843 page = gfn_to_page(kvm, gpa >> PAGE_SHIFT);
844 if (!page)
845 return gpa | HPA_ERR_MASK;
846 return ((hpa_t)page_to_pfn(page) << PAGE_SHIFT)
847 | (gpa & (PAGE_SIZE-1));
848 }
849
850 hpa_t gva_to_hpa(struct kvm_vcpu *vcpu, gva_t gva)
851 {
852 gpa_t gpa = vcpu->mmu.gva_to_gpa(vcpu, gva);
853
854 if (gpa == UNMAPPED_GVA)
855 return UNMAPPED_GVA;
856 return gpa_to_hpa(vcpu->kvm, gpa);
857 }
858
859 struct page *gva_to_page(struct kvm_vcpu *vcpu, gva_t gva)
860 {
861 gpa_t gpa = vcpu->mmu.gva_to_gpa(vcpu, gva);
862
863 if (gpa == UNMAPPED_GVA)
864 return NULL;
865 return pfn_to_page(gpa_to_hpa(vcpu->kvm, gpa) >> PAGE_SHIFT);
866 }
867
868 static void nonpaging_new_cr3(struct kvm_vcpu *vcpu)
869 {
870 }
871
872 static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, hpa_t p)
873 {
874 int level = PT32E_ROOT_LEVEL;
875 hpa_t table_addr = vcpu->mmu.root_hpa;
876
877 for (; ; level--) {
878 u32 index = PT64_INDEX(v, level);
879 u64 *table;
880 u64 pte;
881
882 ASSERT(VALID_PAGE(table_addr));
883 table = __va(table_addr);
884
885 if (level == 1) {
886 pte = table[index];
887 if (is_shadow_present_pte(pte) && is_writeble_pte(pte))
888 return 0;
889 mark_page_dirty(vcpu->kvm, v >> PAGE_SHIFT);
890 page_header_update_slot(vcpu->kvm, table, v);
891 table[index] = p | PT_PRESENT_MASK | PT_WRITABLE_MASK |
892 PT_USER_MASK;
893 rmap_add(vcpu, &table[index], v >> PAGE_SHIFT);
894 return 0;
895 }
896
897 if (table[index] == shadow_trap_nonpresent_pte) {
898 struct kvm_mmu_page *new_table;
899 gfn_t pseudo_gfn;
900
901 pseudo_gfn = (v & PT64_DIR_BASE_ADDR_MASK)
902 >> PAGE_SHIFT;
903 new_table = kvm_mmu_get_page(vcpu, pseudo_gfn,
904 v, level - 1,
905 1, 0, &table[index]);
906 if (!new_table) {
907 pgprintk("nonpaging_map: ENOMEM\n");
908 return -ENOMEM;
909 }
910
911 table[index] = __pa(new_table->spt) | PT_PRESENT_MASK
912 | PT_WRITABLE_MASK | PT_USER_MASK;
913 }
914 table_addr = table[index] & PT64_BASE_ADDR_MASK;
915 }
916 }
917
918 static void nonpaging_prefetch_page(struct kvm_vcpu *vcpu,
919 struct kvm_mmu_page *sp)
920 {
921 int i;
922
923 for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
924 sp->spt[i] = shadow_trap_nonpresent_pte;
925 }
926
927 static void mmu_free_roots(struct kvm_vcpu *vcpu)
928 {
929 int i;
930 struct kvm_mmu_page *page;
931
932 if (!VALID_PAGE(vcpu->mmu.root_hpa))
933 return;
934 #ifdef CONFIG_X86_64
935 if (vcpu->mmu.shadow_root_level == PT64_ROOT_LEVEL) {
936 hpa_t root = vcpu->mmu.root_hpa;
937
938 page = page_header(root);
939 --page->root_count;
940 vcpu->mmu.root_hpa = INVALID_PAGE;
941 return;
942 }
943 #endif
944 for (i = 0; i < 4; ++i) {
945 hpa_t root = vcpu->mmu.pae_root[i];
946
947 if (root) {
948 root &= PT64_BASE_ADDR_MASK;
949 page = page_header(root);
950 --page->root_count;
951 }
952 vcpu->mmu.pae_root[i] = INVALID_PAGE;
953 }
954 vcpu->mmu.root_hpa = INVALID_PAGE;
955 }
956
957 static void mmu_alloc_roots(struct kvm_vcpu *vcpu)
958 {
959 int i;
960 gfn_t root_gfn;
961 struct kvm_mmu_page *page;
962
963 root_gfn = vcpu->cr3 >> PAGE_SHIFT;
964
965 #ifdef CONFIG_X86_64
966 if (vcpu->mmu.shadow_root_level == PT64_ROOT_LEVEL) {
967 hpa_t root = vcpu->mmu.root_hpa;
968
969 ASSERT(!VALID_PAGE(root));
970 page = kvm_mmu_get_page(vcpu, root_gfn, 0,
971 PT64_ROOT_LEVEL, 0, 0, NULL);
972 root = __pa(page->spt);
973 ++page->root_count;
974 vcpu->mmu.root_hpa = root;
975 return;
976 }
977 #endif
978 for (i = 0; i < 4; ++i) {
979 hpa_t root = vcpu->mmu.pae_root[i];
980
981 ASSERT(!VALID_PAGE(root));
982 if (vcpu->mmu.root_level == PT32E_ROOT_LEVEL) {
983 if (!is_present_pte(vcpu->pdptrs[i])) {
984 vcpu->mmu.pae_root[i] = 0;
985 continue;
986 }
987 root_gfn = vcpu->pdptrs[i] >> PAGE_SHIFT;
988 } else if (vcpu->mmu.root_level == 0)
989 root_gfn = 0;
990 page = kvm_mmu_get_page(vcpu, root_gfn, i << 30,
991 PT32_ROOT_LEVEL, !is_paging(vcpu),
992 0, NULL);
993 root = __pa(page->spt);
994 ++page->root_count;
995 vcpu->mmu.pae_root[i] = root | PT_PRESENT_MASK;
996 }
997 vcpu->mmu.root_hpa = __pa(vcpu->mmu.pae_root);
998 }
999
1000 static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, gva_t vaddr)
1001 {
1002 return vaddr;
1003 }
1004
1005 static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
1006 u32 error_code)
1007 {
1008 gpa_t addr = gva;
1009 hpa_t paddr;
1010 int r;
1011
1012 r = mmu_topup_memory_caches(vcpu);
1013 if (r)
1014 return r;
1015
1016 ASSERT(vcpu);
1017 ASSERT(VALID_PAGE(vcpu->mmu.root_hpa));
1018
1019
1020 paddr = gpa_to_hpa(vcpu->kvm, addr & PT64_BASE_ADDR_MASK);
1021
1022 if (is_error_hpa(paddr))
1023 return 1;
1024
1025 return nonpaging_map(vcpu, addr & PAGE_MASK, paddr);
1026 }
1027
1028 static void nonpaging_free(struct kvm_vcpu *vcpu)
1029 {
1030 mmu_free_roots(vcpu);
1031 }
1032
1033 static int nonpaging_init_context(struct kvm_vcpu *vcpu)
1034 {
1035 struct kvm_mmu *context = &vcpu->mmu;
1036
1037 context->new_cr3 = nonpaging_new_cr3;
1038 context->page_fault = nonpaging_page_fault;
1039 context->gva_to_gpa = nonpaging_gva_to_gpa;
1040 context->free = nonpaging_free;
1041 context->prefetch_page = nonpaging_prefetch_page;
1042 context->root_level = 0;
1043 context->shadow_root_level = PT32E_ROOT_LEVEL;
1044 context->root_hpa = INVALID_PAGE;
1045 return 0;
1046 }
1047
1048 static void kvm_mmu_flush_tlb(struct kvm_vcpu *vcpu)
1049 {
1050 ++vcpu->stat.tlb_flush;
1051 kvm_x86_ops->tlb_flush(vcpu);
1052 }
1053
1054 static void paging_new_cr3(struct kvm_vcpu *vcpu)
1055 {
1056 pgprintk("%s: cr3 %lx\n", __FUNCTION__, vcpu->cr3);
1057 mmu_free_roots(vcpu);
1058 }
1059
1060 static void inject_page_fault(struct kvm_vcpu *vcpu,
1061 u64 addr,
1062 u32 err_code)
1063 {
1064 kvm_x86_ops->inject_page_fault(vcpu, addr, err_code);
1065 }
1066
1067 static void paging_free(struct kvm_vcpu *vcpu)
1068 {
1069 nonpaging_free(vcpu);
1070 }
1071
1072 #define PTTYPE 64
1073 #include "paging_tmpl.h"
1074 #undef PTTYPE
1075
1076 #define PTTYPE 32
1077 #include "paging_tmpl.h"
1078 #undef PTTYPE
1079
1080 static int paging64_init_context_common(struct kvm_vcpu *vcpu, int level)
1081 {
1082 struct kvm_mmu *context = &vcpu->mmu;
1083
1084 ASSERT(is_pae(vcpu));
1085 context->new_cr3 = paging_new_cr3;
1086 context->page_fault = paging64_page_fault;
1087 context->gva_to_gpa = paging64_gva_to_gpa;
1088 context->prefetch_page = paging64_prefetch_page;
1089 context->free = paging_free;
1090 context->root_level = level;
1091 context->shadow_root_level = level;
1092 context->root_hpa = INVALID_PAGE;
1093 return 0;
1094 }
1095
1096 static int paging64_init_context(struct kvm_vcpu *vcpu)
1097 {
1098 return paging64_init_context_common(vcpu, PT64_ROOT_LEVEL);
1099 }
1100
1101 static int paging32_init_context(struct kvm_vcpu *vcpu)
1102 {
1103 struct kvm_mmu *context = &vcpu->mmu;
1104
1105 context->new_cr3 = paging_new_cr3;
1106 context->page_fault = paging32_page_fault;
1107 context->gva_to_gpa = paging32_gva_to_gpa;
1108 context->free = paging_free;
1109 context->prefetch_page = paging32_prefetch_page;
1110 context->root_level = PT32_ROOT_LEVEL;
1111 context->shadow_root_level = PT32E_ROOT_LEVEL;
1112 context->root_hpa = INVALID_PAGE;
1113 return 0;
1114 }
1115
1116 static int paging32E_init_context(struct kvm_vcpu *vcpu)
1117 {
1118 return paging64_init_context_common(vcpu, PT32E_ROOT_LEVEL);
1119 }
1120
1121 static int init_kvm_mmu(struct kvm_vcpu *vcpu)
1122 {
1123 ASSERT(vcpu);
1124 ASSERT(!VALID_PAGE(vcpu->mmu.root_hpa));
1125
1126 if (!is_paging(vcpu))
1127 return nonpaging_init_context(vcpu);
1128 else if (is_long_mode(vcpu))
1129 return paging64_init_context(vcpu);
1130 else if (is_pae(vcpu))
1131 return paging32E_init_context(vcpu);
1132 else
1133 return paging32_init_context(vcpu);
1134 }
1135
1136 static void destroy_kvm_mmu(struct kvm_vcpu *vcpu)
1137 {
1138 ASSERT(vcpu);
1139 if (VALID_PAGE(vcpu->mmu.root_hpa)) {
1140 vcpu->mmu.free(vcpu);
1141 vcpu->mmu.root_hpa = INVALID_PAGE;
1142 }
1143 }
1144
1145 int kvm_mmu_reset_context(struct kvm_vcpu *vcpu)
1146 {
1147 destroy_kvm_mmu(vcpu);
1148 return init_kvm_mmu(vcpu);
1149 }
1150 EXPORT_SYMBOL_GPL(kvm_mmu_reset_context);
1151
1152 int kvm_mmu_load(struct kvm_vcpu *vcpu)
1153 {
1154 int r;
1155
1156 mutex_lock(&vcpu->kvm->lock);
1157 r = mmu_topup_memory_caches(vcpu);
1158 if (r)
1159 goto out;
1160 mmu_alloc_roots(vcpu);
1161 kvm_x86_ops->set_cr3(vcpu, vcpu->mmu.root_hpa);
1162 kvm_mmu_flush_tlb(vcpu);
1163 out:
1164 mutex_unlock(&vcpu->kvm->lock);
1165 return r;
1166 }
1167 EXPORT_SYMBOL_GPL(kvm_mmu_load);
1168
1169 void kvm_mmu_unload(struct kvm_vcpu *vcpu)
1170 {
1171 mmu_free_roots(vcpu);
1172 }
1173
1174 static void mmu_pte_write_zap_pte(struct kvm_vcpu *vcpu,
1175 struct kvm_mmu_page *page,
1176 u64 *spte)
1177 {
1178 u64 pte;
1179 struct kvm_mmu_page *child;
1180
1181 pte = *spte;
1182 if (is_shadow_present_pte(pte)) {
1183 if (page->role.level == PT_PAGE_TABLE_LEVEL)
1184 rmap_remove(vcpu->kvm, spte);
1185 else {
1186 child = page_header(pte & PT64_BASE_ADDR_MASK);
1187 mmu_page_remove_parent_pte(child, spte);
1188 }
1189 }
1190 set_shadow_pte(spte, shadow_trap_nonpresent_pte);
1191 kvm_flush_remote_tlbs(vcpu->kvm);
1192 }
1193
1194 static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
1195 struct kvm_mmu_page *page,
1196 u64 *spte,
1197 const void *new, int bytes,
1198 int offset_in_pte)
1199 {
1200 if (page->role.level != PT_PAGE_TABLE_LEVEL)
1201 return;
1202
1203 if (page->role.glevels == PT32_ROOT_LEVEL)
1204 paging32_update_pte(vcpu, page, spte, new, bytes,
1205 offset_in_pte);
1206 else
1207 paging64_update_pte(vcpu, page, spte, new, bytes,
1208 offset_in_pte);
1209 }
1210
1211 static bool last_updated_pte_accessed(struct kvm_vcpu *vcpu)
1212 {
1213 u64 *spte = vcpu->last_pte_updated;
1214
1215 return !!(spte && (*spte & PT_ACCESSED_MASK));
1216 }
1217
1218 void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
1219 const u8 *new, int bytes)
1220 {
1221 gfn_t gfn = gpa >> PAGE_SHIFT;
1222 struct kvm_mmu_page *page;
1223 struct hlist_node *node, *n;
1224 struct hlist_head *bucket;
1225 unsigned index;
1226 u64 *spte;
1227 unsigned offset = offset_in_page(gpa);
1228 unsigned pte_size;
1229 unsigned page_offset;
1230 unsigned misaligned;
1231 unsigned quadrant;
1232 int level;
1233 int flooded = 0;
1234 int npte;
1235
1236 pgprintk("%s: gpa %llx bytes %d\n", __FUNCTION__, gpa, bytes);
1237 kvm_mmu_audit(vcpu, "pre pte write");
1238 if (gfn == vcpu->last_pt_write_gfn
1239 && !last_updated_pte_accessed(vcpu)) {
1240 ++vcpu->last_pt_write_count;
1241 if (vcpu->last_pt_write_count >= 3)
1242 flooded = 1;
1243 } else {
1244 vcpu->last_pt_write_gfn = gfn;
1245 vcpu->last_pt_write_count = 1;
1246 vcpu->last_pte_updated = NULL;
1247 }
1248 index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES;
1249 bucket = &vcpu->kvm->mmu_page_hash[index];
1250 hlist_for_each_entry_safe(page, node, n, bucket, hash_link) {
1251 if (page->gfn != gfn || page->role.metaphysical)
1252 continue;
1253 pte_size = page->role.glevels == PT32_ROOT_LEVEL ? 4 : 8;
1254 misaligned = (offset ^ (offset + bytes - 1)) & ~(pte_size - 1);
1255 misaligned |= bytes < 4;
1256 if (misaligned || flooded) {
1257 /*
1258 * Misaligned accesses are too much trouble to fix
1259 * up; also, they usually indicate a page is not used
1260 * as a page table.
1261 *
1262 * If we're seeing too many writes to a page,
1263 * it may no longer be a page table, or we may be
1264 * forking, in which case it is better to unmap the
1265 * page.
1266 */
1267 pgprintk("misaligned: gpa %llx bytes %d role %x\n",
1268 gpa, bytes, page->role.word);
1269 kvm_mmu_zap_page(vcpu->kvm, page);
1270 continue;
1271 }
1272 page_offset = offset;
1273 level = page->role.level;
1274 npte = 1;
1275 if (page->role.glevels == PT32_ROOT_LEVEL) {
1276 page_offset <<= 1; /* 32->64 */
1277 /*
1278 * A 32-bit pde maps 4MB while the shadow pdes map
1279 * only 2MB. So we need to double the offset again
1280 * and zap two pdes instead of one.
1281 */
1282 if (level == PT32_ROOT_LEVEL) {
1283 page_offset &= ~7; /* kill rounding error */
1284 page_offset <<= 1;
1285 npte = 2;
1286 }
1287 quadrant = page_offset >> PAGE_SHIFT;
1288 page_offset &= ~PAGE_MASK;
1289 if (quadrant != page->role.quadrant)
1290 continue;
1291 }
1292 spte = &page->spt[page_offset / sizeof(*spte)];
1293 while (npte--) {
1294 mmu_pte_write_zap_pte(vcpu, page, spte);
1295 mmu_pte_write_new_pte(vcpu, page, spte, new, bytes,
1296 page_offset & (pte_size - 1));
1297 ++spte;
1298 }
1299 }
1300 kvm_mmu_audit(vcpu, "post pte write");
1301 }
1302
1303 int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva)
1304 {
1305 gpa_t gpa = vcpu->mmu.gva_to_gpa(vcpu, gva);
1306
1307 return kvm_mmu_unprotect_page(vcpu->kvm, gpa >> PAGE_SHIFT);
1308 }
1309
1310 void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
1311 {
1312 while (vcpu->kvm->n_free_mmu_pages < KVM_REFILL_PAGES) {
1313 struct kvm_mmu_page *page;
1314
1315 page = container_of(vcpu->kvm->active_mmu_pages.prev,
1316 struct kvm_mmu_page, link);
1317 kvm_mmu_zap_page(vcpu->kvm, page);
1318 }
1319 }
1320
1321 static void free_mmu_pages(struct kvm_vcpu *vcpu)
1322 {
1323 struct kvm_mmu_page *page;
1324
1325 while (!list_empty(&vcpu->kvm->active_mmu_pages)) {
1326 page = container_of(vcpu->kvm->active_mmu_pages.next,
1327 struct kvm_mmu_page, link);
1328 kvm_mmu_zap_page(vcpu->kvm, page);
1329 }
1330 free_page((unsigned long)vcpu->mmu.pae_root);
1331 }
1332
1333 static int alloc_mmu_pages(struct kvm_vcpu *vcpu)
1334 {
1335 struct page *page;
1336 int i;
1337
1338 ASSERT(vcpu);
1339
1340 if (vcpu->kvm->n_requested_mmu_pages)
1341 vcpu->kvm->n_free_mmu_pages = vcpu->kvm->n_requested_mmu_pages;
1342 else
1343 vcpu->kvm->n_free_mmu_pages = vcpu->kvm->n_alloc_mmu_pages;
1344 /*
1345 * When emulating 32-bit mode, cr3 is only 32 bits even on x86_64.
1346 * Therefore we need to allocate shadow page tables in the first
1347 * 4GB of memory, which happens to fit the DMA32 zone.
1348 */
1349 page = alloc_page(GFP_KERNEL | __GFP_DMA32);
1350 if (!page)
1351 goto error_1;
1352 vcpu->mmu.pae_root = page_address(page);
1353 for (i = 0; i < 4; ++i)
1354 vcpu->mmu.pae_root[i] = INVALID_PAGE;
1355
1356 return 0;
1357
1358 error_1:
1359 free_mmu_pages(vcpu);
1360 return -ENOMEM;
1361 }
1362
1363 int kvm_mmu_create(struct kvm_vcpu *vcpu)
1364 {
1365 ASSERT(vcpu);
1366 ASSERT(!VALID_PAGE(vcpu->mmu.root_hpa));
1367
1368 return alloc_mmu_pages(vcpu);
1369 }
1370
1371 int kvm_mmu_setup(struct kvm_vcpu *vcpu)
1372 {
1373 ASSERT(vcpu);
1374 ASSERT(!VALID_PAGE(vcpu->mmu.root_hpa));
1375
1376 return init_kvm_mmu(vcpu);
1377 }
1378
1379 void kvm_mmu_destroy(struct kvm_vcpu *vcpu)
1380 {
1381 ASSERT(vcpu);
1382
1383 destroy_kvm_mmu(vcpu);
1384 free_mmu_pages(vcpu);
1385 mmu_free_memory_caches(vcpu);
1386 }
1387
1388 void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot)
1389 {
1390 struct kvm_mmu_page *page;
1391
1392 list_for_each_entry(page, &kvm->active_mmu_pages, link) {
1393 int i;
1394 u64 *pt;
1395
1396 if (!test_bit(slot, &page->slot_bitmap))
1397 continue;
1398
1399 pt = page->spt;
1400 for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
1401 /* avoid RMW */
1402 if (pt[i] & PT_WRITABLE_MASK) {
1403 rmap_remove(kvm, &pt[i]);
1404 pt[i] &= ~PT_WRITABLE_MASK;
1405 }
1406 }
1407 }
1408
1409 void kvm_mmu_zap_all(struct kvm *kvm)
1410 {
1411 struct kvm_mmu_page *page, *node;
1412
1413 list_for_each_entry_safe(page, node, &kvm->active_mmu_pages, link)
1414 kvm_mmu_zap_page(kvm, page);
1415
1416 kvm_flush_remote_tlbs(kvm);
1417 }
1418
1419 void kvm_mmu_module_exit(void)
1420 {
1421 if (pte_chain_cache)
1422 kmem_cache_destroy(pte_chain_cache);
1423 if (rmap_desc_cache)
1424 kmem_cache_destroy(rmap_desc_cache);
1425 if (mmu_page_header_cache)
1426 kmem_cache_destroy(mmu_page_header_cache);
1427 }
1428
1429 int kvm_mmu_module_init(void)
1430 {
1431 pte_chain_cache = kmem_cache_create("kvm_pte_chain",
1432 sizeof(struct kvm_pte_chain),
1433 0, 0, NULL);
1434 if (!pte_chain_cache)
1435 goto nomem;
1436 rmap_desc_cache = kmem_cache_create("kvm_rmap_desc",
1437 sizeof(struct kvm_rmap_desc),
1438 0, 0, NULL);
1439 if (!rmap_desc_cache)
1440 goto nomem;
1441
1442 mmu_page_header_cache = kmem_cache_create("kvm_mmu_page_header",
1443 sizeof(struct kvm_mmu_page),
1444 0, 0, NULL);
1445 if (!mmu_page_header_cache)
1446 goto nomem;
1447
1448 return 0;
1449
1450 nomem:
1451 kvm_mmu_module_exit();
1452 return -ENOMEM;
1453 }
1454
1455 #ifdef AUDIT
1456
1457 static const char *audit_msg;
1458
1459 static gva_t canonicalize(gva_t gva)
1460 {
1461 #ifdef CONFIG_X86_64
1462 gva = (long long)(gva << 16) >> 16;
1463 #endif
1464 return gva;
1465 }
1466
1467 static void audit_mappings_page(struct kvm_vcpu *vcpu, u64 page_pte,
1468 gva_t va, int level)
1469 {
1470 u64 *pt = __va(page_pte & PT64_BASE_ADDR_MASK);
1471 int i;
1472 gva_t va_delta = 1ul << (PAGE_SHIFT + 9 * (level - 1));
1473
1474 for (i = 0; i < PT64_ENT_PER_PAGE; ++i, va += va_delta) {
1475 u64 ent = pt[i];
1476
1477 if (ent == shadow_trap_nonpresent_pte)
1478 continue;
1479
1480 va = canonicalize(va);
1481 if (level > 1) {
1482 if (ent == shadow_notrap_nonpresent_pte)
1483 printk(KERN_ERR "audit: (%s) nontrapping pte"
1484 " in nonleaf level: levels %d gva %lx"
1485 " level %d pte %llx\n", audit_msg,
1486 vcpu->mmu.root_level, va, level, ent);
1487
1488 audit_mappings_page(vcpu, ent, va, level - 1);
1489 } else {
1490 gpa_t gpa = vcpu->mmu.gva_to_gpa(vcpu, va);
1491 hpa_t hpa = gpa_to_hpa(vcpu, gpa);
1492
1493 if (is_shadow_present_pte(ent)
1494 && (ent & PT64_BASE_ADDR_MASK) != hpa)
1495 printk(KERN_ERR "xx audit error: (%s) levels %d"
1496 " gva %lx gpa %llx hpa %llx ent %llx %d\n",
1497 audit_msg, vcpu->mmu.root_level,
1498 va, gpa, hpa, ent,
1499 is_shadow_present_pte(ent));
1500 else if (ent == shadow_notrap_nonpresent_pte
1501 && !is_error_hpa(hpa))
1502 printk(KERN_ERR "audit: (%s) notrap shadow,"
1503 " valid guest gva %lx\n", audit_msg, va);
1504
1505 }
1506 }
1507 }
1508
1509 static void audit_mappings(struct kvm_vcpu *vcpu)
1510 {
1511 unsigned i;
1512
1513 if (vcpu->mmu.root_level == 4)
1514 audit_mappings_page(vcpu, vcpu->mmu.root_hpa, 0, 4);
1515 else
1516 for (i = 0; i < 4; ++i)
1517 if (vcpu->mmu.pae_root[i] & PT_PRESENT_MASK)
1518 audit_mappings_page(vcpu,
1519 vcpu->mmu.pae_root[i],
1520 i << 30,
1521 2);
1522 }
1523
1524 static int count_rmaps(struct kvm_vcpu *vcpu)
1525 {
1526 int nmaps = 0;
1527 int i, j, k;
1528
1529 for (i = 0; i < KVM_MEMORY_SLOTS; ++i) {
1530 struct kvm_memory_slot *m = &vcpu->kvm->memslots[i];
1531 struct kvm_rmap_desc *d;
1532
1533 for (j = 0; j < m->npages; ++j) {
1534 unsigned long *rmapp = &m->rmap[j];
1535
1536 if (!*rmapp)
1537 continue;
1538 if (!(*rmapp & 1)) {
1539 ++nmaps;
1540 continue;
1541 }
1542 d = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
1543 while (d) {
1544 for (k = 0; k < RMAP_EXT; ++k)
1545 if (d->shadow_ptes[k])
1546 ++nmaps;
1547 else
1548 break;
1549 d = d->more;
1550 }
1551 }
1552 }
1553 return nmaps;
1554 }
1555
1556 static int count_writable_mappings(struct kvm_vcpu *vcpu)
1557 {
1558 int nmaps = 0;
1559 struct kvm_mmu_page *page;
1560 int i;
1561
1562 list_for_each_entry(page, &vcpu->kvm->active_mmu_pages, link) {
1563 u64 *pt = page->spt;
1564
1565 if (page->role.level != PT_PAGE_TABLE_LEVEL)
1566 continue;
1567
1568 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
1569 u64 ent = pt[i];
1570
1571 if (!(ent & PT_PRESENT_MASK))
1572 continue;
1573 if (!(ent & PT_WRITABLE_MASK))
1574 continue;
1575 ++nmaps;
1576 }
1577 }
1578 return nmaps;
1579 }
1580
1581 static void audit_rmap(struct kvm_vcpu *vcpu)
1582 {
1583 int n_rmap = count_rmaps(vcpu);
1584 int n_actual = count_writable_mappings(vcpu);
1585
1586 if (n_rmap != n_actual)
1587 printk(KERN_ERR "%s: (%s) rmap %d actual %d\n",
1588 __FUNCTION__, audit_msg, n_rmap, n_actual);
1589 }
1590
1591 static void audit_write_protection(struct kvm_vcpu *vcpu)
1592 {
1593 struct kvm_mmu_page *page;
1594 struct kvm_memory_slot *slot;
1595 unsigned long *rmapp;
1596 gfn_t gfn;
1597
1598 list_for_each_entry(page, &vcpu->kvm->active_mmu_pages, link) {
1599 if (page->role.metaphysical)
1600 continue;
1601
1602 slot = gfn_to_memslot(vcpu->kvm, page->gfn);
1603 gfn = unalias_gfn(vcpu->kvm, page->gfn);
1604 rmapp = &slot->rmap[gfn - slot->base_gfn];
1605 if (*rmapp)
1606 printk(KERN_ERR "%s: (%s) shadow page has writable"
1607 " mappings: gfn %lx role %x\n",
1608 __FUNCTION__, audit_msg, page->gfn,
1609 page->role.word);
1610 }
1611 }
1612
1613 static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg)
1614 {
1615 int olddbg = dbg;
1616
1617 dbg = 0;
1618 audit_msg = msg;
1619 audit_rmap(vcpu);
1620 audit_write_protection(vcpu);
1621 audit_mappings(vcpu);
1622 dbg = olddbg;
1623 }
1624
1625 #endif
Linux kernel - Deliverables
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